Backflow preventer and test cock assembly

Abstract

A backflow prevention test assembly for a backflow preventer has a test valve in fluid communication with a conduit of the backflow preventer and a test kit. The test valve has a body defining an axial bore, and a piston defining a test conduit is disposed within the axial bore for movement between a first position permitting test flow through the test conduit and a second position resisting test flow. The piston is biased toward the second position. The test kit includes a test apparatus and a fitting for attachment upon the test valve body in sealing engagement. The fitting defines a displacement surface for engagement, after sealing engagement of the seal with the test valve, with an opposed surface of the piston to urge the piston toward its first position, thereby to establish fluid communication between the test apparatus and a region of the backflow preventer conduit. A method of testing fluid within the flow conduit of the backflow preventer is also described.

What is claimed is: 
     
       1. A backflow prevention test assembly for use with a backflow preventer comprising a body defining a conduit for flow of fluid between an inlet and an outlet, a first valve and a second valve disposed in sequence in the conduit, the first valve having a first position permitting flow in a first direction and a second position opposing flow in a second direction opposite the first direction, with first means for biasing the first valve toward the second position, and the second valve having a first position permitting flow in the first direction and a second position for opposing flow in the second direction, with second means for biasing the second valve toward the second position, said backflow prevention test assembly comprising: at least one test valve in fluid communication with the conduit through an aperture defined by the backflow preventer body,     said test valve comprising a test valve body defining an axial bore, said test valve body having a male end and an outer surface having a male thread,   a piston defining a test conduit and disposed within said axial bore for movement between a first position permitting test flow through said test conduit and a second position resisting test flow through said test conduit, and   means for biasing said piston toward said second position, and     a test kit assembly comprising a test apparatus, and a fitting sized for threaded attachment upon said male end of said test valve body in sealing engagement, said fitting comprising a fitting seal positioned for sealing engagement with said test valve, and said fitting defining a displacement surface disposed for engagement, after sealing engagement of said fitting seal with said test valve, with an opposed surface of said piston in a manner to urge said piston toward said first position, thereby to establish fluid communication between said test apparatus and a region of the conduit within the backflow preventer body.     
     
     
       2. The apparatus of claim 1 wherein said means for biasing comprises a spring mounted within said test valve body to act against said piston, said spring compressed by movement of said piston toward said first position. 
     
     
       3. The apparatus of claim 1 wherein said test valve further comprises an o-ring seal positioned for sealing engagement between said piston and an interior wall of said test valve body. 
     
     
       4. The apparatus of claim 1 wherein said test valve body defines a second threaded section for integrating said test valve into said backflow prevention assembly. 
     
     
       5. The apparatus of claim 1 wherein said test valve further comprises a protective cap for attachment upon said test valve body to protect said piston against movement toward said first position. 
     
     
       6. A method for selectively allowing access to a fluid within a body of a backflow prevention apparatus, said method comprising the steps of: providing a test cock integrated into the body of the apparatus, the test cock comprising a test valve body defining an axial bore, said test valve body having a male end and an outer surface having a male thread, a piston defining a test conduit and disposed within the axial bore for movement between a first position permitting test flow through the test conduit and a second position resisting test flow through the test conduit, means for biasing the piston toward the second position, and a protective cap for attachment upon the test valve body to protect the piston against movement toward the first position,   removing the protective cap from the test valve body element to expose the piston,   threadedly attaching a test device to the male end of the test valve body, said test device including a fitting seal such that attachment of the test device to the test valve body first achieves a seal with the test valve and thereafter displaces the piston toward the first position to permit flow of fluid from within the body of the backflow preventer, through the axial bore of the piston to the test device,   after testing, disconnecting the test device from the test valve body in a manner whereby a seal is first obtained to resist flow of fluid from within the body of the backflow preventer into the test conduit, and thereafter the test device is disengaged from the test valve body, and   reattaching the protective cap.   
     
     
       7. A backflow prevention test assembly for use with a backflow preventer comprising a body defining a conduit for flow of fluid between an inlet and an outlet, a first valve and a second valve disposed in sequence in the conduit, the first valve having a first position permitting flow in a first direction and a second position opposing flow in a second direction opposite the first direction, with first means for biasing the first valve toward the second position, and the second valve having a first position permitting flow in the first direction and a second position for opposing flow in the second direction, with second means for biasing the second valve toward the second position, said backflow prevention test assembly comprising: at least one test valve in fluid communication with the conduit through an aperture defined by the backflow preventer body,     said test valve comprising a test valve body defining an axial bore, said test valve body having a male end and an outer surface having a male thread,   a piston defining a test conduit and disposed within said axial bore for movement between a first position permitting test flow through said test conduit and a second position resisting test flow through said test conduit,   means for biasing said piston toward said second position, and   an inner seal positioned for sealing engagement between said piston and an interior wall of said test valve body, said inner seal preventing fluid communication between said conduit and said test valve with said piston in said second position, and     a test kit assembly comprising a test apparatus, and a fitting sized for threaded attachment upon said male end of said test valve body in sealing engagement, said fitting comprising a fitting seal positioned for sealing engagement with said test valve, and said fitting defining a displacement surface disposed for engagement, after sealing engagement of said fitting seal with said test valve, with an opposed surface of said piston in a manner to urge said piston toward said first position, thereby to establish fluid communication between said test apparatus and a region of the conduit within the backflow preventer body.